摘要:

Mark-recovery methodology, accounting for mortality, enabled annual estimates of estuarine winter flounder (Pseudopleuronectes americanus) abundance at summer's end. Recruitment from the estuarine system to an inshore-offshore otter trawl fishery occurred incompletely (73%) over three age groups (II-IV). The release of tagged pre-recruits in two consecutive years and subsequent return data, adjusted for non-reporting of tag recoveries, yielded the following 1970 post-recruit, instantaneous mortality parameters: total = 0.3570, fishing = 0.2445, natural = 0.1125. A comparison of total recruitment from southeastern Massachusetts flounder groups, derived from a population estimate and instantaneous total mortality rate, with recruitment from the Waquoit Bay-Eel Pond system indicated that the latter constituted less than one percent of the total required to maintain equilibrium catch.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<647:WFEYAM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

This paper describes a vinyl streamer tag for use on shrimp (Penaeus spp.). The tag is light and flexible, and has little if any effect on shrimp movement or behavior. In laboratory tests, the streamer was retained by the shrimp and caused no detectable tagging mortality, while considerable mortality occurred in shrimp tagged with a Petersen tag. In field tests over a 30-day period, there were limited dislocation and loss of streamer tags, but the dye used to color the vinyl material faded. Suggestions for modification of the streamer tag are made to alleviate these two problems. Mortality in shrimp tagged with the streamer did not differ significantly from that of untagged shrimp.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<658:AVSTFS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

The simple ratio estimate of the total number of marked fish present in a catch is described and the variance estimates discussed. A maximum likelihood estimate of the total number of marks present in a catch is derived which combines both marks found in samples and marks voluntarily returned from the non-sampled portion of the catch. The use of this estimate is illustrated with data from the salmon sport fishery in Puget Sound.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<664:ETTNOM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

In an evaluation of overwinter survival of fin-clipped and unmarked brook trout in a reclaimed pond in Maine, 10,000 fall fingerlings were divided into 20 treatment groups, 19 of which were marked by the removal of either single or multiple fins. Analysis of returns from creel and trap-net sampling indicated that: (1) survival of unmarked, unanesthetized trout was significantly higher than that of marked, anesthetized fish; (2) survival of trout with multiple fin excisions was lower than that of fish with single fin excisions; (3) removal of the adipose fin had little or no effect on survival; and (4) removal of a pectoral fin was no more detrimental than the removal of a ventral fin. Spring recaptures indicated that fish of all groups were equally vulnerable to both sampling methods. Overwinter survival was low for all groups.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<669:OSOFBT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

From 1972 to 1975, an estimated 39–47% of the adult rainbow trout (Salmo gairdneri) in Sagehen Creek spawned in an intermittent stream—Kiln Meadow Tributary—while several permanently flowing tributaries attracted only 10–15% of the run. The balance of the fish presumably spawn in the upper reaches of the main stream. Kiln Meadow Tributary drains a south-facing slope, and peak runoff from snow melt occurs early. This may be one factor that attracts spawning fish. The absence of competition from brook trout, which cannot spawn in Kiln Meadow Tributary in the fall, may enhance the value of this watercourse for rearing young rainbow trout.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<675:TQIOAI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Florida largemouth bass, Micropterus salmoides floridanus, fail to spawn in association with dense populations of stunted sunfish. A recent study indicated that a “physical factor” rather than a chemical factor may be responsible.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<682:BSOSIL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Mosquitofish, the only fish species inhabiting a drainage system that received high coal ash concentration at one end and thermal discharges at the other, appeared to successfully function in this environment with no apparent detrimental effects. Temperature conditions (44.5 C) were more limiting to the species' functional capacity than was coal ash turbidity (275 JTU) with high metal concentrations.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<686:ROMGAT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Studies of deposition of dieldrin concentrations sublethal to fish were conducted in flowing and non-flowing aquatic systems. Residual concentrations were determined for water, soil, plants, and fish in 18 flowing and 18 static artificial systems, after treatments of 24, 36, 48, and 72 h, in a farm pond. Samples from each of the four components were analyzed for dieldrin residues by gas chromatography. Two aquaria with aerated water but without biological components were tested.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<695:DODIFC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

An inexpensive bioassay system was developed to estimate pollutant effects on a benthic animal. Mirex, a fire ant toxicant, was taken into the substrate by the burrowing and feeding activity of the lugworm, Arenicola cristata, and significantly affected this activity. Mirex was present in the adult worm as well as in its juvenile stage.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<700:TEOMOT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Based on information gained from a pilot model, two identical revolving plate filters were designed to be evaluated for use in a recirculated fish production system. Each unit consisted of a fiberglass tank containing 787 liters of water; a biofilter having 60 plates, each 51 cm in diameter, rotated at 6 rpm; and a settling tank. The total water volume in each unit was 1,132 liters. Water was continuously passed through the filter at a rate of 9 liters/min, and fresh water was added to the fish tank at a rate of 0.45 to 0.72 liters/min. In a trial designed to determine loading rate, it was found that each of the units could support at least 45 g of channel catfish (Ictalurus punctatus) per liter of the total volume of water in the system, and approximately 2 kg/m2of surface area of the filter. By extrapolation, carrying capacity on the basis of fresh-water flush was 71 to 113 kg/liter/min. In a growth trial, the fish in both units grew at an acceptable rate for the temperature at which they were held. In both trials, ammonia, nitrite nitrogen, nitrate nitrogen, methyl orange alkalinity, pH, and oxygen remained at desirable levels. It appears that this type of filter has some features that are particularly attractive for use in recirculated fish production units or holding facilities.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<704:EOARPT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor